It is known that molecular oxygen will influence the intensity of luminescence of a large number of organic substances, e.g., polycyclic aromatic hydrocarbons. In such cases the molecular oxygen will interact with the molecule activated by the excitation light, drawing energy from the excited molecule and reducing the intensity of the fluorescent light emitted. It is also known that the Partial pressure of the molecular oxygen may be measured via the luminescence intensity of such an indicator substance. The luminescent material may be supplied in a solvent or embedded in a membrane. The partial pressure of the oxygen contained in the solvent or membrane will determine the degree of luminescence intensity.
This invention relates to membranes and films which are permeable to oxygen, and which are prepared from an organic modified silicic acid heteropolycondensate. Although certain heteropolycondensates of this type have been described in the art, it is believed that the advantageous oxygen permeability of such materials has not been previously discovered. It is also believed that these materials have not been previously employed for oxygen sensing.